I don't think they can just drop the R/S and stay listed on Nasdaq after the merger. A post-merger entity is required to satisfy all of NASDAQ's initial listing criteria and complete the initial listing process, including the minimum $4 bid price requirement for initial listing.
According to the merger-agreement, ANI requires BPAX to make sure they will stay listed on the Nasdaq after the merger, in order to get the merger closed. Hence my concern for ANI thinking of the merger as a 'free IPO' and the benefits that come with that (i.e. issuing shares to raise cash).